Edwin Armstrong: Genius of FM Radio
APRIL 01, 1990 by JORGE AMADOR
Jorge Amador is a free-lance writer and editor of The Pragmatist, a current-affairs bimonthly.
This year marks the centennial of the birth of Edwin Howard Armstrong. Though his name is recognized by few today, his influence is literally all around us. What makes Armstrong’s centennial significant is that, more than any other person, he was responsible for the broadcasting revolution.
Described as one of the last great free-lance “attic inventors,” Armstrong is credited not only with originating many of the devices that made it possible to transmit and receive long-distance radio signals, but also with developing one of the major modes of transmission—wide-channel frequency modulation, which we know popularly as FM.
Armstrong’s story, however, goes beyond that of a great inventor cranking out new gadgets for the good of mankind from the isolation of a lab. For Armstrong’s FM radio was nearly killed at birth by a combination of fearful competitors and government. His is a cautionary tale illustrating the power to cripple not just one man’s business, but an entire industry, when the state controls access to the basic resources that the industry develops.
His father sold Bibles and his mother was a schoolteacher, but from an early age Edwin Armstrong showed great aptitude for mechanical things, and by the time he was 14 he was set on a career in “wireless.” Like other amateur radio enthusiasts at the turn of the century, Armstrong put together crude sets from coils and tubes, and spent countless hours in his Yonkers, New York, home listening intently for the faint dots and dashes of faraway Morse code transmissions.
In 1912, during experiments to increase his set’s reception power, Armstrong, then an electrical engineering student at Columbia University, devised an improvement over the existing Audion vacuum tube. The regenerative or “feedback” circuit, his first invention, amplified the strength of incoming signals hundreds of times, enough to do away with the bother of earphones and to pick up signals from across the Atlantic.
Six years later, as a captain in the U.S. Army Signal Corps, Armstrong was asked to find a way to intercept German military radio communications, which were transmitted in frequencies too high for Allied receivers. Out of his research came the superheterodyne, another circuit with greatly improved amplification which is still the standard in radio, television, and radar sets. Together, the regenerative and superheterodyne circuits made modern broadcasting possible and secured Armstrong’s place in the annals of telecommunications.
Among the select audience to whom Armstrong introduced the regenerative circuit was David Sarnoff, the future president of the Radio Corporation of America. The two became friends. Over the next decade, while Armstrong built his reputation as an inventor, Sarnoff rose to the top of RCA. One day in 1922 Sarnoff, frustrated over the problem of static interference with radio broadcasts, said to Armstrong, “I wish that someone would come up with a little black box to eliminate static.”
Armstrong was well aware of the problem. Simple static electricity, such as that caused by lightning and electrical appliances, overwhelmed standard AM signals, and there appeared to be no way to get rid of it. Radio engineers, in fact, were resigned to it, and sought to reduce rather than eliminate static interference. “Static, like the poor, will always be with us,” lamented one.
But Armstrong found a way. The scope of this article doesn’t permit a technical discussion, but the gist of Armstrong’s discovery was this: Instead of modulating (varying) the amplitude (strength) of the radio wave, Armstrong proposed to modulate a different aspect, its frequency (hence the term “frequency modulation”). FM transmissions, he discovered, weren’t subject to interference from sources of static. The “little black box” was a whole new broadcasting technology.
The Advantages of FM
Armstrong’s FM has other important esthetic and economic advantages over AM:
- Because it operates on a wider frequency band, FM can reproduce almost the entire range of sound audible to the human ear, a feature we call high fidelity.
- In a process known as multiplexing, used for instance to provide music for stores and offices, the wider band enables the FM operator to send more than one signal at a time.
- Because of the way FM-generated waves propagate through the air, an FM station can serve a greater area than an AM station with the same power, or the same area with less power, making FM stations cheaper to operate.
- Yet FM stations on the same frequency can be placed closer together geographically than AM stations, because unlike AM their signals don’t interfere with each other. In FM we hear only the stronger station, rarely both at the same time.
In 1933 Armstrong took out four patents on FM and presented Sarnoff and RCA with his invention, hopeful that his friend would take the lead in promoting the revolutionary new medium. RCA decided to test it, and in March 1934 invited Armstrong to set up his equipment at the company’s Empire State Building facilities. Performance results exceeded Armstrong’s claims.
Then, writes broadcast historian Erik Barnouw, in April 1935 the inventor “was ‘politely’ asked to remove his equipment. . . . That same month RCA announced its allocation of $1,000,000 for television tests.” TV was the new rage; nothing more about FM was forthcoming from RCA for another four years. Armstrong was angry over being induced to waste his time by a company that had no interest in developing his invention.
Determined to show the value of FM, Armstrong asked the Federal Communications Commission (FCC) for spectrum space for further FM experiments and sought permission to build his own station. At hearings in 1936, Sarnoff confirmed Armstrong’s suspicions. He testified against allocating space to FM and urged that it be given to television instead.
From RCA’s perspective, the matter was simple. As put by Don V. Erickson, author of Armstrong’s Fight for FM Broadcasting, “RCA did not own the patents on FM. It did own the patents on television.” Thus the company stood to keep a greater share of any profits to be made from television than from FM radio. Moreover, since it was a vastly superior radio service, FM represented a threat to established AM operations—in which RCA, as the parent company of the NBC network, had made great investments.
Thus, explains Erickson, “in almost every overt and covert action, it can be seen that RCA (and the majority of the AM industry) were trying desperately to forestall something that would either cut down, or cut out, their operation.” Not least among these efforts was to choke off FM’s access to the airwaves, which was controlled by the FCC.
At this point it is useful to note that this and subsequent fights for spectrum space between FM and television were uniquely a product of government involvement. In the regime of spectrum socialism, under which “the public” is said to “own” the airwaves and a government agency (the FCC) administers them, those who wish to try a new broadcast service, even if they don’t propose to take up frequencies currently in use, must go to the FCC for permission to operate.
Absent the FCC, if more than one set of operators wished to use the same general area of the electromagnetic spectrum, they could agree among themselves to divide up the virgin space in question. Or they could simply begin independently to operate at specific frequencies, establish by their use a claim to them as if the frequencies were homesteaded territory, and then if necessary trade or sell frequencies to achieve a consolidated band. In this way, there’s room for everybody. Nobody can stake out all the possible frequencies for himself at once, or prevent another from staking out his own space.
Spectrum socialism, however, makes the allocation process controversial. It forces each party to thrash it out at the FCC, where the incentive is to try to get everything that’s available. After all, if you must go to the effort and expense of making your case at a hearing—and particularly if you are in competition with others—you might as well ask for all the frequencies at hand, in the hope of ending up with more than you might need. Suddenly there’s not enough room for everybody, “justifying” the existence of the allocating agency that encouraged the problem. With this approach, one man’s gain becomes another’s loss.
The system also gives you the chance to shut out the competition by decree, as RCA attempted. Eventually the FCC allocated television 120 mega-cycles for experiments, while FM received just 2.7. The agency at first even denied Armstrong a license to build a station, but finally relented in the face of persistent efforts by the inventor.
Armstrong then proceeded to build his station, W2XMN at Alpine, New Jersey, to demonstrate FM’s possibilities. Shortly after it began transmitting in July 1939, interest in FM soared. Armstrong commissioned General Electric to build 25 FM receiving sets at his own expense. GE liked the new medium so much that it began to prepare for mass production. The Yankee Network built another station in Massachusetts and began broadcasting in FM to New England.
By the fall of that year, the FCC had more than 150 applications to build FM stations. The space it had parsimoniously allocated to FM three years before was plainly not enough to satisfy existing demand. FM had arrived. Meanwhile, television was a curiosity at the 1939 World’s Fair.
As Fortune magazine commented in October 1939:
[W]hile granting the reasonableness of a certain hesitancy, the observer cannot help remarking that the industry has been infuriatingly reactionary in its attitude towards Major Armstrong’s development. . . . Moreover, the fact that RCA kept this inventor hanging on the end of a string, without committing itself definitely, was certainly not conducive to progress on the technological frontier. . . .
While the duty of the FCC in making shortwave band allocations was clearly to get television on the air as quickly as possible, the Commission’s failure to understand frequency modulation, and to place the proper estimate on its technological importance, is just as deplorable as the industry’s failure to push it. . . . What FM needs at the present time above all things is an allocation that will put it on a commercial status and will at the same time be large enough to permit it to operate to full advantage.
On May 20, 1940, the FCC finally gave rein to FM. It took Channel I off the television band and allotted it to FM. The Commission assigned FM the frequencies between 42 and 50 megahertz, enough for 40 FM channels, and authorized commercial service beginning January 1, 1941.
The future looked bright for FM. Other radio set manufacturers, including Zenith and Western Electric (but not RCA, as we shall see), arranged royalty deals. Despite the United States’ entry into World War II, the number of commercial FM stations doubled from 18 in 1941 to 36 in 1942, and grew to 46 in 1945. According to Time magazine, more than a half-million FM radio receivers were then in use.
Then came a shocker: In January 1945 the FCC proposed to kick FM up into the range of frequencies around 100 megahertz, and to give television additional space in the vacated area. This precipitated a third spectrum battle between FM and television.
The stated reason for the proposed move was the concern that, at FM’s current frequencies, radio transmissions would be particularly vulnerable to interference caused by sunspots. It was necessary to make the move immediately, since the height of the next sunspot cycle was expected in 1948–49.
The Commission called hearings for the spring of 1945. It established a Radio Technical Planning Board in several subcommittees to evaluate the proposed general spectrum reallocation. Panel 5, which investigated the claims of sunspot interference, found the evidence lacking and voted 27 to 1 against moving FM. The Board as a whole also recommended against the move.
Armstrong’s biographer, Lawrence Lessing, notes that AM interests featured prominently in the pro-FM move camp: “But a long string of witnesses, including representatives of CBS, ABC, Cowles Broadcasting, Crosley, Philco, Motorola, and DuMont, urged that FM be moved ‘upstairs.’”
Despite the findings of its own experts and the strenuous opposition of Armstrong and the FM industry, the FCC went ahead with the move in 1945, ostensibly on the basis of the testimony of one engineer who later admitted his calculations had been wrong. The FCC then assigned this band, from which FM radio was banished “for its own good,” to television, which Lessing notes was “about twenty-five times more sensitive to any kind of interference than FM and which, moreover, was still required to use FM on its sound channel.”
The dreaded interference never showed up, but the effect of the move on FM was disastrous. With one stroke the FCC “made obsolescent every FM radio receiver, every FM transmitter, and a major part of all FM equipment and tubes,” writes Erickson. “Thus, with no new FM equipment on the lucrative postwar market and no advertisers to purchase time on the new band of frequencies, FM in its first ten years of existence was brought close to the brink of commercial death.” Shortly after the FM shift was proposed, The New York Times reported that “The total investment of the country in transmitters, receivers and other [FM] paraphernalia was estimated ‘in the region of $50,000,000 to $100,000,000.’” A spokesman for the Frequency Modulation Broadcasters Inc. predicted in February 1945 that the move “would cost prospective buyers of FM receiving sets $100,000,000 more than if they would be permitted to buy sets now designed as soon as they could be made available after the war.”
In a brief filed with the FCC, the broadcasters complained that “The change would cost a paralyzing delay during the post-war years when FM could move forward with great rapidity.” The delay, in fact, would prove devastating. “FM practically had to start all over again,” observed the Times’ radio critic in 1949. Erickson describes the situation:
As though [FM was] just invented, equipment had to be put on the drawing board and experimented with to develop sophistication in these very high frequencies; stations had to be reconverted before they could program; and most drastic, the public had to be convinced all over again that FM was worth the purchase of another radio. In this great postwar market, then, AM broadcasting was able to step in and fill part of the great demand for new entertainment, with television coming up a fast second.
“The RCA-NBC forces . . . rejoiced,” adds Barnouw. “The new development tended to protect the status quo in radio while providing spectrum space for the expansion of television.”
The 1945 spectrum shift presaged a series of postwar decisions by the FCC, all founded upon the state’s control over the airwaves, which tended further to hamstring the FM industry. That same year the agency approved a “Single Market Plan,” proposed by another AM network, the Columbia Broadcasting System, to limit the power and reach of FM stations to a single city or market.
The effect of this was to put FM at a further competitive disadvantage vis-à-vis AM. While many AM stations continued to be allowed to send their signals through “clear channels” across the continent, FM stations were prevented from attracting advertiser revenue by serving a wider area.
Radio set manufacturers were prohibited by the FCC from easing the frequency transition by building sets that could tune in to both the old and the new hands. In April 1951, the Commission prohibited FM stations from multiplexing signals to stores, offices, and other establishments, a nascent source of revenue for cash-starved operators. (The ban was lifted in July 1955.)
Before the war the invisible hand of the market had pointed to a rosy future, but the iron fist of the state nearly choked FM at birth, then pushed it into the broadcasting wilderness for decades. Three years after the spectrum shift, independent FM stations were reporting $1.1 million in total revenues—and $4.2 million in expenses, for a staggering loss of three times total revenue. FM’s revenue did not approach even half its expenses until 1952, and the industry as a whole did not begin to make a profit until 1976. Television and AM radio enjoyed the fruits of the postwar entertainment market. The number of TV stations jumped from 12 in 1947 to 494 in 1957, and AM stations increased from 1062 to 3008. Meanwhile nearly 200 FM stations, which, despite the handicaps, had opened in postwar enthusiasm, found it necessary to close up shop.
RCA, which first ignored FM and then asked the FCC to rule it out of the airwaves, eventually accepted the new medium as a fact of life and started to manufacture FM receivers, as well as televisions with the required FM sound. Sarnoff had offered Armstrong a flat fee of $1,000,000 for a license to use his FM system when it was first approved for commercial use in 1940, but Armstrong preferred a royalty arrangement. Subsequently RCA tried to negotiate similar deals a number of times, but Armstrong always refused, on the grounds that it would be unfair to other manufacturers who were paying royalties on sales.
However, RCA had a firm policy of making cash settlements. RCA, writes Barnouw, “did not pay royalties; it collected them.” The company patented a rival FM system it claimed was different from Armstrong’s, and licensed that to other manufacturers. So, although Edwin Armstrong held the basic patents on frequency modulation, RCA paid him nothing, and instead collected from others. Armstrong’s final battle was on.
The inventor published a technical paper showing that RCA’s product embodied no new principle and was essentially a copy of his. In July 1948, he sued RCA and NBC for patent infringement.
The pretrial proceedings dragged on for more than five years. “Armstrong, normally patient,” writes Barnouw, “became a man possessed. All his energies came to be centered on the suit. Three o’clock in the morning would find him poring over transcripts. At all hours he called attorneys to discuss tactics.”
The bitter, protracted struggle diverted Armstrong from his research, spent his fortune and health, and alienated his family and friends, who urged him to settle for his own sake. Late in January 1954, literally sick and tired, Armstrong surrendered. He gave his lawyer the go-ahead to explore a settlement. On the night of January 31, he dressed for the cold night and stepped out—out the window of his 13th-floor New York City apartment. His body was found the next morning. A few months later, RCA paid Armstrong’s estate $1,040,000 and the case was closed. 
For Further Reading:
Erik Barnouw, The Golden Web: A History of Broadcasting in the United States 1933–1953 (New York: Oxford University Press, 1968)
Don V. Erickson, Armstrong’s Fight for FM Broadcasting: One Man vs. Big Business and Bureaucracy (University of Alabama Press, 1973)
Sydney W. Head, Broadcasting in America.’ A Survey of Television and Radio (Boston: Houghton Mifflin, 1972)
Edward A. Herron, Miracle of the Air Waves: A History of Radio (New York: Julian Messner, 1969)
Lawrence P. Lessing, Man of High Fidelity: Edwin Howard Armstrong (Philadelphia: Lippincott, 1956)
Christopher H. Sterling, Electronic Media: A Guide to Trends in Broadcasting and Newer Technologies 1920–1983 (New York: Praeger, 1984)